1. Field of the Invention
The present invention relates to a boot inner liner whose upper is made from one or several pieces which are cut out along a predetermined contour, then mounted together by means of stitches, adhesive, welding, etc., for example.
2. Description of Background and Relevant Information
Liners of the above-mentioned type are widely implemented in sport boots having a more or less rigid outer envelope, commonly called a "shell." These liners are adapted to ensure the interface between the shell and the user's foot. They are especially provided with a sole on which the upper is "glued-welded" and, in order to allow passage of the user's foot, their upper is provided, just like the boot shells, with a foot entry opening in its upper front part. In fact, it is these liners that determine the comfort and technicality of the boot.
In a known manner, these characteristics of comfort and technicality are obtained by adjusting the thickness and firmness of the wall of the liner upper, which can be obtained from one or several pieces of different types. More specifically, the upper is most often constituted of one or several pieces which are cut out along a pattern, according to a predetermined contour, then the upper is formed and mounted by assembly means that define stitchings, gluing, welding, etc., i.e., connecting lines.
By this arrangement, each cut out and/or outlined piece can be provided with specific characteristics perfectly adapted to the areas of the foot that it covers and to the technical effects anticipated in the shell-foot interface. By way of example, patent EP 0 427 321 and utility certificate FR 2 719 198 teach these types of liners.
Also known are liners whose upper is formed with one or several pieces molded along a predetermined contour, these pieces being potentially pre-shaped, then formed and mounted by assembly means that define the connecting lines, such as stitching, welding, etc. Still, by way of example, patents IT 1 138 921 and IT 1 138 107, which disclose liners made in this manner, can be cited.
These different ways of obtaining the upper of liners from one or several previously cut out pieces, which are then mounted by assembly means, allow modifying and adjusting the size and/or fitting volume by merely correcting, right before mounting, the contour of the different component piece and/or pieces, and possibly varying very substantially the relative position of the assembly means on the contour of the pieces. In addition, they allow designing liners with an upper whose structure is composed of several pieces of different types and characteristics that are predetermined depending on the sensitivity of various zones of the user's foot and the technical effects sought. Thus, the parameters of comfort and technicality can be easily respected.
For all of these advantageous reasons, manufacturing ease, great freedom of composition, easy adjustment, etc., most of the known liners have their upper formed and mounted by assembly means after the component piece and/or pieces have been cut out.
These liners, however, are found to be badly adapted when impermeability of the boot is sought. This is especially the case for boots adapted to be used in snow, such as boots for alpine skiing, mountain skiing, and cross-country skiing. Indeed, in these boots the only protection offered by the shell remains insufficient since the zone or the foot entry opening of the shell, like that of the liner, requires the use of elements for overlapping and maintaining the foot which must be movable to allow the passage of the foot. Due to this mobility of the overlapping elements in the foot entry of the shell, it is therefore not possible to provide a permanent impermeability at the area of their mutual junction and across from the shell from which they originate. Consequently, the water resulting from melted snow can easily infiltrate and penetrate inside the shell by the front thereof through the overlapping elements, either when using the boot or when putting it on or taking it off, and reach the liner through its foot entry zone, and at its toe. The covering elements for the foot entry of the liner, as well as the outer surface of the latter, are therefore subjected to the same water infiltration problem which, obviously, permeates itself easily through the pores and interstices that remain, especially along the connecting lines defined by the assembly means.